Question

A wheel, starting from rest, rotates with a uniform angular acceleration of $2rad{s}^{-2}$. The number of rotations it performs in the tenth second is

• A. 3
• B. 6
• C. 9
• D. 12

Answer 1

Answer: (A)

3

${\omega }_0=0$
${\theta }_n={\omega }_0+\frac{1}{2}\alpha (2n-1)$
${\theta }_{10}=\frac{\alpha }{2}(2n-1)=\frac{2}{2}(2\times 10-1)=19rad$
Number of revolutions: $\frac{19}{2\pi }=3$